Voltage adaptive unmanned aerial vehicle image transmission energy saving system and method and unmanned aerial vehicle

Abstract

The application provides a voltage self-adaptive unmanned aerial vehicle image transmission energy-saving system and method and an unmanned aerial vehicle. The system comprises a control unit, a radio frequency front-end module, an adjustable voltage power supply system and an electronic switch circuit. The adjustable voltage power supply system comprises a DC-DC converter with a feedback circuit. The control unit controls the electronic switch circuit to selectively connect one of multiple feedback resistors to the feedback circuit according to the acquired transmission power of the radio frequency front-end module, so as to adjust the output voltage of the DC-DC converter and realize dynamic matching between the transmission power and the power supply voltage. The application solves the problem of high power consumption caused by fixed voltage power supply in the existing image transmission system. Through dynamic matching between the voltage and the power, the system power consumption is significantly reduced, the endurance time of the unmanned aerial vehicle is prolonged, and the communication quality and system stability are ensured.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) communication technology, specifically to a voltage-adaptive UAV image transmission energy-saving system, method, and UAV, and in particular to a voltage-adaptive, power-saving small UAV image transmission system, which is especially suitable for miniaturized UAV communication scenarios with strict power consumption requirements. Background Technology

[0002] Small drones, especially micro drones, have their flight endurance severely limited by battery capacity. Among the various power-consuming modules of a drone, the image transmission system is one of the main power consumers. To reduce the power consumption of the image transmission system, existing technologies generally employ closed-loop power control schemes. This involves dynamically adjusting the transmission power of the radio frequency front-end module based on the communication distance and signal quality between the drone and the ground station, while maintaining a fixed supply voltage. When the communication link quality is good, the transmission power is reduced; when the link quality deteriorates, the transmission power is increased to maintain communication.

[0003] However, the above solutions have significant drawbacks. Even during low-power transmission or no-load operation, the power amplifier inside the RF front-end module still exhibits a high quiescent current, resulting in non-negligible static power consumption. In fixed-voltage power supply mode, regardless of how low the transmission power is adjusted, this static power consumption, determined by the supply voltage and quiescent current, always exists, leading to energy waste and limited overall energy-saving effect, failing to fundamentally solve the endurance problem of small drones. Furthermore, while precise power management solutions exist in other fields, their input / output voltage ranges are typically incompatible with the wide-voltage batteries commonly used in drones and the operating voltage requirements of the image transmission RF front-end module, thus preventing direct application. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a voltage-adaptive image transmission energy-saving system, method, and drone for unmanned aerial vehicles (UAVs).

[0005] A voltage-adaptive UAV image transmission energy-saving system according to the present invention includes: A control unit for acquiring the transmit power of the radio frequency front-end module; An RF front-end module; An adjustable power supply system for powering the RF front-end module, the adjustable power supply system including a DC-DC converter with feedback circuitry; and An electronic switching circuit is connected between the control unit and the feedback circuit; The feedback circuit includes multiple feedback resistors; The control unit is configured to: control the electronic switching circuit according to the acquired transmit power, so as to selectively connect one of the plurality of feedback resistors to the feedback circuit, thereby adjusting the output voltage of the DC-DC converter so that the transmit power of the RF front-end module matches the power supply voltage supplied to it.

[0006] Preferably, the control unit is configured to achieve low power transmission corresponding to low supply voltage and high power transmission corresponding to high supply voltage.

[0007] Preferably, the control unit is further configured to: Monitor the transmit signal quality parameter EVM of the RF front-end module, and when the monitored EVM is less than a first preset threshold, control the adjustable power supply system to increase the output voltage; and / or The signal-to-noise ratio (SNR) data is received and processed through the data interface of the ground end of the image transmission module. When the processed SNR is less than a second preset threshold, the adjustable power supply system is controlled to increase the output voltage.

[0008] Preferably, the control unit uses a power switching hysteresis threshold when adjusting the output voltage according to the transmission power.

[0009] Preferably, the electronic switching circuit includes a single-pole multi-throw analog switch controlled by the GPIO pin of the control unit.

[0010] This invention also provides a voltage-adaptive UAV image transmission energy-saving method, employing the aforementioned voltage-adaptive UAV image transmission energy-saving system, comprising the following steps: Receive an instruction to determine the target transmit power required by the radio frequency front-end module; Based on the target transmission power, determine a target power supply voltage that matches it; The adjustable power supply system is controlled to output the target power supply voltage to the radio frequency front-end module.

[0011] Preferably, the step of determining the target power supply voltage follows the principle of matching low transmission power with low power supply voltage and high transmission power with high power supply voltage.

[0012] Preferred options also include: The system monitors the transmit signal quality parameter EVM of the RF front-end module in real time, and when the monitored EVM is less than a first preset threshold, increases the output voltage of the adjustable power supply system based on the current target supply voltage; and / or The system receives signal-to-noise ratio (SNR) data through a data interface of the image transmission system, and when the received SNR is less than a second preset threshold, it increases the output voltage of the adjustable power supply system based on the current target power supply voltage.

[0013] Preferably, in the control step, when switching the target power supply voltage, a power switching hysteresis threshold is used for judgment, and the power switching hysteresis threshold is 0.5dB.

[0014] The present invention also provides a drone, including the above-described voltage-adaptive drone image transmission energy-saving system.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention significantly reduces power consumption and extends battery life. By achieving dynamic matching between power supply voltage and transmission power, this invention effectively eliminates the static power consumption waste of the radio frequency front-end module in low-power operation, which can significantly reduce the power consumption of the image transmission system and thus effectively improve the overall battery life of the UAV.

[0016] 2. This invention can ensure communication quality. While saving energy, this invention introduces closed-loop monitoring of communication quality parameters such as EVM and SNR, which can actively increase the voltage when the signal quality deteriorates to ensure the stability of the link and the data throughput, thus ensuring the smoothness of image transmission.

[0017] 3. The system of the present invention has high stability. By setting a power switching hysteresis threshold, the present invention effectively avoids unnecessary frequent voltage jumps near the power critical point, thus ensuring the stable operation of the power supply system.

[0018] 4. This invention achieves low cost and easy integration. It utilizes low-cost and versatile components such as general-purpose pins of the main control unit, standard electronic switches, and resistors to form a high-efficiency voltage regulation system. It does not require expensive dedicated power management chips and is easy to integrate and implement on existing UAV image transmission hardware platforms. Attached Figure Description

[0019] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A schematic diagram of the circuit structure of a voltage-adaptive UAV image transmission energy-saving system provided in an embodiment of the present invention; Figures 1A-1F They are respectively Figure 1 Enlarged view of positions A through F in the middle; Figure 2 This is a schematic representation of the control logic truth value of the single-pole eight-throw analog switch used in this embodiment of the invention; Figure 3 This is a schematic flowchart of a voltage adaptive control method provided in an embodiment of the present invention; Figure 4 This is a timing diagram of closed-loop control signaling interaction in an embodiment of the present invention.

[0020] The diagram shows: U1: Main control CPU; U2: RF transceiver; U3: RF front-end module (FEM); U4: Adjustable power supply system; U103: Single-pole eight-throw analog switch; R6: Feedback upper resistor; R7-R13: Feedback lower resistor group; A, B, C: Analog switch control inputs. Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Example 1 This embodiment provides a basic implementation of a voltage-adaptive UAV image transmission energy-saving system. In one embodiment of this application, the core of the solution lies in constructing a power supply system dynamically adjusted by a control unit, so that the voltage supplied to the radio frequency front-end module can match its real-time transmission power, thereby minimizing system power consumption while ensuring communication performance.

[0023] Please see Figure 1 , Figures 1A-1F , Figure 1This embodiment provides a circuit diagram of a voltage-adaptive UAV image transmission energy-saving system. The system mainly includes a main control CPU U1 as a control unit, an RF transceiver U2, an RF front-end module (FEM) U3, an adjustable power supply system U4, and a single-pole eight-throw analog switch U103 as an electronic switching circuit. The main control CPU U1 can be a microcontroller or dedicated processor with sufficient general-purpose input / output pins, such as the ARS31L chip from Coolchip Microelectronics. The RF transceiver U2, for example, can be the AR8030 chip from Coolchip Microelectronics, which generates the RF baseband signal to be transmitted and sends it to the RF front-end module U3. The RF front-end module U3, for example, can be the KCT8585HE chip from Kangxi Communications, which integrates power amplifiers and other circuits to receive the signal from the RF transceiver U2, amplify it, and then transmit it through connector J1, which serves as the antenna interface. It should be noted that the RF front-end module U3 is the main source of power consumption in the image transmission system, and the technical solution of this application mainly optimizes its power consumption.

[0024] It is understandable that the core of this system lies in the voltage adaptive regulation circuit composed of the main control CPU U1, the adjustable power supply system U4, the single-pole eight-throw analog switch U103, and a set of feedback resistors. Specifically, in this embodiment, the adjustable power supply system U4 uses a synchronous buck DC-DC converter, such as the SCT2464 chip from Chipsys Technology. This converter can convert the higher voltage provided by the drone battery (such as a 2S lithium battery, whose voltage range is typically between 6.0V and 8.4V) into the operating voltage required by the RF front-end module U3. The output voltage of the DC-DC converter depends on its feedback circuit. This feedback circuit consists of a fixed-value feedback upper resistor R6 and a variable feedback lower resistor. One end of the feedback upper resistor R6 is connected to the output terminal of the adjustable power supply system U4, and the other end is connected to its feedback pin. This connection point also serves as the common input terminal of the single-pole eight-throw analog switch U103.

[0025] As a key actuator for voltage switching, the single-pole eight-throw analog switch U103 (e.g., using the CD4051B chip from Huaguan Semiconductor) has a common terminal, eight selectable output channels (seven of which are used in this embodiment, i.e., channels 0 to 6), and three digital control input pins A, B, and C. These three control input pins are electrically connected to the three general-purpose input / output pins of the main control CPU U1. The seven output channels of the analog switch U103 are each connected to one of a set of feedback resistors R7-R13 with different resistance values, while the other ends of these feedback resistors are all grounded.

[0026] Based on this connection method, the main control CPU U1 can control the single-pole eight-throw analog switch U103 to select different channels by changing the logic level combination of its three general-purpose input / output pins, thereby connecting a specific resistor from the feedback resistor group R7-R13 into the feedback loop of the DC-DC converter. Its adjustment principle follows the typical DC-DC converter output voltage formula:

[0027] in, For output voltage, This is the internal reference voltage of the DC-DC converter (e.g., the reference voltage of the SCT2464 is 1.0V). The value of the feedback resistor R6 is given. This refers to the resistance value of the feedback resistor selected by analog switch U103. In this embodiment, the resistance value of the feedback resistor R6 is fixed (e.g., 100kΩ). Therefore, by switching the feedback resistor with different resistance values... This allows for precise adjustment of the output voltage. .

[0028] Please refer to the following: Figure 2 , Figure 2 The control logic truth table of the CD4051B single-pole eight-throw analog switch is shown. The main control CPU U1 can precisely select the channel to be turned on by outputting a 3-bit binary code to control inputs A, B, and C. For example, when the CPU outputs a logic level "000", channel 0 is turned on; when it outputs "110", channel 6 is turned on. It should be noted that in this embodiment, the resistance values ​​of the feedback resistor group R7-R13 are carefully designed to correspond to seven different voltage levels that are meaningful for the operation of the RF front-end module U3. For example, seven voltage levels can be set: 3.3V, 3.6V, 3.8V, 4.0V, 4.2V, 4.5V, and 5.0V. These seven voltage levels are achieved by connecting resistors R13 to R7. For example, when a maximum output voltage of 5.0V is required, the main control CPU U1 outputs a control signal "110", and the analog switch U103 then connects channel 6, thereby connecting the feedback resistor R7 (e.g., 24.9kΩ) with the smallest resistance to the circuit. According to the aforementioned formula, the following can be calculated: Accordingly, when a minimum output voltage of 3.3V is required, the main control CPU U1 outputs a control signal "000", the analog switch U103 connects channel 0, and the feedback resistor R13 with the largest resistance (its resistance is set to approximately 43.5kΩ) is connected to the circuit, thereby enabling... .

[0029] The following will combine Figure 3The flowchart shown illustrates the system's operation. During UAV flight, the image transmission system determines the required target transmission power based on factors such as the distance between the UAV and the ground station, and signal attenuation, using a closed-loop power control algorithm. This process corresponds to... Figure 3 Step S102: Obtain the required transmit power P_tx. The main control CPU U1 has a pre-stored power-voltage correspondence table, which is based on experimental data (as shown in Table 2 in the core elements). This table specifies the minimum acceptable supply voltage for different transmit power ranges, provided that the transmit signal quality parameters (e.g., error vector amplitude EVM) are qualified. This process corresponds to... Figure 3 Step S103: Query the preset table to determine the target voltage V_target.

[0030] For example, when a drone takes off or hovers at close range, the system determines that only 10dBm of transmit power is needed to maintain good communication. At this time, the main control CPU U1 consults its internal power-voltage table to determine that the minimum acceptable voltage corresponding to the power range of 10dBm to 15dBm is 3.3V. Based on this, the CPU U1 sets 3.3V as the target voltage and outputs logic level "000" to the control pins A, B, and C of the single-pole eight-throw analog switch U103 according to the preset control logic. This operation selects channel 0 of the analog switch U103, thereby connecting the feedback resistor R13 to the feedback loop, and thus precisely adjusting the output voltage of the adjustable power supply system U4 to 3.3V, supplying it to the RF front-end module U3.

[0031] Accordingly, as the drone flies further, link loss increases, requiring the system to increase its transmission power. Assuming the required power increases to 25dBm, the main control CPU U1 consults the power-voltage mapping table again, determining that a 5.0V supply voltage is needed to guarantee signal quality at maximum power for the 24dBm to 28dBm power range. Therefore, CPU U1 updates the target voltage to 5.0V and outputs a control signal "110" to analog switch U103 to switch to channel 6, connecting the feedback resistor R7 to the circuit. This allows the output voltage of the adjustable power supply system U4 to quickly (typically within 1 millisecond) increase to 5.0V. The above control process corresponds to... Figure 3 Step S104: Control the analog switch to set the output voltage to V_target.

[0032] Through this adaptive control strategy of "matching low transmission power with low supply voltage and high transmission power with high supply voltage," this embodiment achieves significant energy-saving effects. According to experimental data (as shown in Table 1 of the core elements), when the transmission power is 10dBm, the power consumption of the RF front-end module U3 is approximately 1000mW if a traditional fixed 5V power supply is used; however, by adopting the solution in this embodiment, which reduces the voltage to 3.3V, the power consumption is reduced to approximately 594mW, a reduction of up to 40.6%. During the entire flight mission, the UAV is not at its maximum communication distance for most of the time; therefore, the image transmission system can operate at lower voltage and power for most of the time. Calculations show that this solution can reduce the total power consumption of the image transmission system by 30% to 60%, ultimately effectively increasing the overall flight time of the UAV by more than 20%.

[0033] Example 2 This embodiment provides a voltage-adaptive, power-saving small UAV image transmission system, including a main control CPU, an RF transceiver, an RF front-end module (FEM), an adjustable power supply system, and an antenna interface. The signal output terminal of the RF transceiver is electrically connected to the RF input pin of the FEM; the RF output pin of the FEM is electrically connected to the antenna interface; the power supply system is electrically connected to the power input pins of the main control CPU, the RF transceiver, and the FEM; the three GPIO pins of the main control CPU are electrically connected to the control pins of a single-pole eight-throw (SPET) analog switch; one end of the feedback resistor of the DC-DC converter in the power supply system is electrically connected to the power output, and the other end is electrically connected to the common terminal of the SPET analog switch. The seven output terminals of the SPET analog switch are respectively electrically connected to feedback resistors of different resistance values.

[0034] Furthermore, based on the FEM RF transmission power of the front-end module, the main control CPU controls the power system voltage of the front-end module through three GPIO interfaces, quickly and in real time matching the appropriate voltage to the front-end module. Simply put, low power corresponds to low voltage, and high power corresponds to high voltage, thereby reducing the power consumption of the image transmission module.

[0035] Furthermore, the main control CPU is the ARS31L from Coolchip Microelectronics; the RF transceiver is the AR8030 from Coolchip Microelectronics; and the front-end module (FEM) is the KCT8585HE from Kangxi Communications.

[0036] Furthermore, when the main control CPU adjusts the voltage, it also refers to the radio frequency transmission signal quality parameter EVM of the radio frequency front-end module FEM and the signal-to-noise ratio SNR of the receiver. When the EVM or SNR exceeds the preset qualified threshold, the power supply voltage is automatically increased until the EVM and SNR return to qualified.

[0037] Furthermore, the output voltage range of the adjustable voltage power supply unit is 3.3V-5V, and the ripple factor is ≤70mV.

[0038] Furthermore, the analog switch unit is a single-pole multi-throw analog switch that supports at least 7 outputs.

[0039] Furthermore, to prevent frequent voltage switching at power proximity points, a power switching threshold of 0.5 dB is set.

[0040] This embodiment discloses a voltage-adaptive, power-saving image transmission system for small unmanned aerial vehicles (UAVs) that solves the problems of high power consumption and short battery life in existing image transmission systems for small UAVs (under 249g). The system includes a main control CPU, an RF transceiver, a radio frequency front-end module (FEM), an adjustable power supply system, and an antenna interface. The main control CPU controls a single-pole eight-throw analog switch via GPIO. By using different feedback resistors corresponding to different channels in the power supply system, the system dynamically adjusts the supply voltage of the FEM, achieving adaptive control of 'low voltage for low transmit power and high voltage for high transmit power'. Simultaneously, it combines the transmitter's EVM and the receiver's SNR to ensure image transmission quality.

[0041] Experiments show that the system in this embodiment can reduce image transmission power consumption by 30%-60% and increase drone flight time by more than 20%, making it suitable for small drone scenarios with strict requirements on power consumption and size.

[0042] Currently, the flight time of small drones is typically less than half an hour. Besides the power unit, the most power-consuming component is usually the drone's image transmission system. Therefore, significantly reducing the power consumption of the image transmission system without affecting the image transmission function can greatly improve the drone's flight time. For some small drones, such as those weighing less than 249g, battery capacity is very limited, and the power consumption of image transmission accounts for an even higher proportion. Current drone image transmission systems typically employ closed-loop power control to reduce power consumption. This means that the front-end module, powered by 5V, uses different transmission power for different distances. The system dynamically matches the transmission power based on the received signal strength and quality. Specifically, while ensuring communication quality, a lower transmission power is used when the received signal strength is high, and vice versa. This strategy partially reduces power consumption, but it still cannot meet the flight time requirements of small drones. In other industries, such as the more mature mobile phone industry, there are MIPI or I2C controlled power modules (DC-CDC). However, the maximum input voltage of such power chips is 5.5V, while drones typically need to be powered by 2S (8.4V fully charged) or 6S (25.2V fully charged) batteries. Furthermore, the output of the power chip only supports a variation from 0.5V to 3.4V, which cannot meet the power supply requirements of the RF front-end module (FEM) commonly used in the drone industry, which ranges from 5V to 3.3V. This necessitates a more innovative solution.

[0043] Using the solution in this embodiment, throughout the entire flight, while ensuring the quality of the wireless communication signal, the main control CPU not only matches the corresponding power based on the strength and quality of the received signal, but also dynamically changes the power supply voltage of the front-end radio frequency module (FEM) in real time through three GPIOs. This significantly reduces the power consumption of the UAV image transmission system throughout the entire flight, increases the UAV's flight time, and greatly improves the user experience.

[0044] Example 3 This embodiment provides a voltage-adaptive, power-saving small UAV image transmission system, including a main control CPU, an RF transceiver, an RF front-end module (FEM), an adjustable power supply system, and an antenna interface. The signal output terminal of the RF transceiver is electrically connected to the RF input pin of the front-end module; the RF output pin of the front-end module is electrically connected to the antenna interface; the power supply system is electrically connected to the power input pins of the main control CPU, the RF transceiver, and the front-end module; the three GPIO pins of the main control CPU are electrically connected to the control pin of a single-pole eight-throw (SPET) analog switch; one end of the feedback resistor of the DC-DC converter in the power supply system is electrically connected to the power output, and the other end is electrically connected to the common terminal of the SPET analog switch. The seven output terminals of the SPET analog switch are each electrically connected to resistors of different resistance values.

[0045] The main control CPU is the ARS31L from Coolchip Microelectronics; the RF transceiver is the AR8030 from Coolchip Microelectronics; and the front-end module is the KCT8585HE from Comstar Communications. The power supply is the SCT2464 from Chipsys Technology. The single-pole eight-throw analog switch is the CD4051B from Huaguan Semiconductor.

[0046] The formula for calculating the output voltage of SCT2464 is: V out =V ref *(R6 / R+1). V out This refers to the output voltage, and R6 refers to the feedback resistor, which is... Figure 1 R6 in the schematic diagram. Where V ref R is the reference voltage (typical value 1.0V) of the DC-DC converter (model SCT2464), R6 is the upper feedback resistor, and R is the lower feedback resistor (i.e., any one of R7-R13); for example: if R6 is fixed at 100kΩ, and a 5V output voltage is required, substitute into the formula 5V=1.0V×(1+100kΩ / R7), and we get R7=24.9kΩ.

[0047] The CD4051B single-pole eight-throw analog switch is controlled by three GPIOs, which are controlled by the three GPIOs of the main control CPU. Of the eight channels of the CD4051B, seven channels (channels 0-6) are connected to R7-R13 (corresponding to 3.3V-5V voltages), and the eighth channel (channel 7) is left floating.

[0048] In a drone's image transmission module, the front-end module, which includes the power amplifier, has the highest power consumption weight. When the power amplifier (PA) of the front-end module is turned on, even with very low or no input power, the static power consumption of the PA is typically greater than 200mA, or 1 watt for a single PA. Image transmission modules usually have two PAs, meaning a static power consumption of 2W. Therefore, at close range, even with very low transmission power, the static power consumption offers little benefit in terms of overall power efficiency.

[0049] The power consumption calculation formula is P = V × I, where P refers to the input power consumption of the PA (unit: watts W), which is the total electrical energy consumed by the PA during operation. V is the supply voltage of the PA (unit: volts V), that is, the operating voltage provided to the PA by the power source. I is the operating current of the PA (unit: amperes A). The formula essentially states that "energy consumption rate = voltage × current." If either voltage or current decreases, as long as the other parameter does not increase significantly in the opposite direction, the power consumption will decrease accordingly. According to Table 1, when the voltage decreases and the current change is not significant, the input power consumption of the PA will decrease directly proportional to the voltage reduction.

[0050] According to Tables 2 and 3, to ensure communication quality and achieve high-definition image transmission (e.g., 1080P60) at a given output power, a relatively high-order modulation scheme (QAM16) is required to guarantee high data throughput. To demodulate QAM16, the transmit quality (EVM) at the transmitting end must first be qualified; otherwise, the signal-to-noise ratio (SNR) at the receiving end will be lower than the demodulation threshold of this modulation scheme by 5dB, the modulation scheme will be reduced to QPSK, the throughput will decrease, and high-definition image transmission will be impossible. This requires the power supply voltage to have a lower limit at the corresponding power level; therefore, the voltage cannot be infinitely small, and the EVM qualification must be prioritized. Thus, the voltage limit of the closed-loop power needs to be evaluated based on the SNR at the receiving end.

[0051] In simple terms, closed-loop power estimates wireless link loss by analyzing the strength and quality of the received signal, indirectly reflecting distance and environmental interference. This is the core basis for power adjustment. Figure 4 As shown, first, the "downlink loss" is estimated (loss = ground-end transmit power - air-end (aircraft-end) receive power); then, the uplink loss is estimated symmetrically: due to the "reciprocity" of the wireless channel (downlink loss and uplink loss are approximately equal), the air-end uses the downlink loss to estimate the "uplink loss".

[0052] Based on the estimated uplink loss, the minimum transmit power required for clear reception at the ground end is calculated. The system configures the voltage in real time according to Table 2: the main control CPU controls the front-end module power system through three GPIO interfaces, quickly and in real time matching the voltage to the front-end module. Simply put, low power corresponds to low voltage, and high power corresponds to high voltage, thereby reducing the power consumption of the image transmission module.

[0053] For example, if the system can maintain communication using a relatively low transmit power (e.g., 10dBm) and a relatively low voltage (e.g., 3.3V), the main control CPU controls three GPIO_A, GPIO_B, and GPIO_C logic levels to 000, and the CD4051B single-pole eight-throw analog switch switches to channel 1, corresponding to a voltage of 3.3V. The voltage of the front-end module decreases from 5V to 3.3V, and because the current change is minimal, the power consumption of the power amplifier (PA) is reduced. Only when the communication distance reaches its limit, requiring a power increase to over 25dBm, does the main control CPU control three GPIO_A, GPIO_B, and GPIO_C logic levels to 011, and the CD4051B single-pole eight-throw analog switch switches to channel 7, corresponding to a voltage of 5.0V. This optimizes the power consumption of the UAV throughout its entire flight while achieving high-definition image transmission and return.

[0054] To prevent frequent voltage switching near power levels, a power switching threshold of 0.5dB is set. For example, when the power increases from 14dBm to 15.1dBm, the voltage remains unchanged; it only switches to 3.6V when the power reaches 15.5dBm. Similarly, a 0.5dB power switching threshold is also required when the power decreases. Experiments have verified that 0.5dB balances response speed and stability; thresholds below 0.5dB tend to switch frequently, while thresholds above 0.5dB negatively impact image transmission quality.

[0055] Table 1

[0056] Table 2

[0057] Table 3

[0058] Table 4

[0059] According to Table 4, the core innovation of this invention is that, using this solution, during the entire flight process, the main control CPU dynamically changes the power supply voltage of the PA through three GPIOs in real time according to the strength and quality of the received signal, quickly matching the closed-loop power of the transmission, which greatly reduces the power consumption of the UAV image transmission system, improves the flight time of the UAV, and greatly improves the user experience.

[0060] Example 4 like Figure 1 The circuit diagram of the UAV image transmission system in this embodiment is shown below. U1 is the main control CPU, specifically the ARS31L from Coolchip Microelectronics; U2 is the RF transceiver, specifically the AR8030 from Coolchip Microelectronics; U3 is the RF front-end module (FEM), specifically the KCT8585HE from Kangxi Communications; U4 is the adjustable voltage power supply system, specifically the SCT2464 from Chipsys Technology; and J1 is the antenna interface.

[0061] like Figure 2 The table shown is the truth table of a single-pole eight-throw analog switch. INH is the enable terminal of the analog switch. When the level is low (0), the switch is active. When the level is high (1), all channels are disconnected. 'ON' CHANNEL (S) corresponds to the channel number of the analog switch. Channels 0-6 correspond to the 3.3V-5V power supply voltage, respectively. Channel 7 is left floating. A, B and C are the control pins of its channel output.

[0062] This embodiment provides a voltage-adaptive, power-saving small UAV image transmission system, including a main control CPU, an RF transceiver, an RF front-end module (FEM), a power supply system, and an antenna interface. The signal output terminal of the RF transceiver is electrically connected to the RF input pin of the FEM; the RF output pin of the FEM is electrically connected to the antenna interface; the power supply system is electrically connected to the power input pins of the main control CPU, the RF transceiver, and the FEM; the three GPIO pins of the main control CPU are electrically connected to the control pins of a single-pole eight-throw (SPET) analog switch; one end of the feedback resistor of the DC-DC converter in the power supply system is electrically connected to the power output, and the other end is electrically connected to the common terminal of the SPET analog switch. The seven output terminals of the SPET analog switch are each electrically connected to resistors of different resistance values. The main control CPU is an ARS31L from Coolchip Microelectronics; the RF transceiver is an AR8030 from Coolchip Microelectronics; and the front-end module is a KCT8585HE from Kangxi Communications.

[0063] The power supply is a SCT2464 from Chipsys Technology, and the single-pole eight-throw analog switch is a CD4051B from Huaguan Semiconductor. The formula for calculating the output voltage of the SCT2464 is: V out =1V*(R6 / R+1). V out This refers to the output voltage, and R6 refers to the feedback resistor, which is... Figure 1 R6 in the schematic diagram. R is the feedback resistor of the SCT2464, which is... Figure 1 The resistors R7, R8, R9, R10, R11, R12, and R13 in the schematic diagram. This means that when the resistance of the feedback resistor changes, the output voltage changes. For example, if R6 is fixed at 100kΩ, and R7 (corresponding to 5V) is selected, substituting into the formula, 5 = 100kΩ / R7 + 1, we get R7 = 24.9kΩ.

[0064] according to Figure 2 The truth table of the CD4051B single-pole eight-throw analog switch shows that GPIO_A, GPIO_B, and GPIO_C select seven different voltages. R7, R8, R9, R10, R11, R12, and R13 correspond to 5V, 4.5V, 4.2V, 4.0V, 3.8V, 3.6V, and 3.3V, respectively. For example, when switching from 5V to 3.3V, the response time for the three logic control levels to change from "110" to "000" is ≤1µs. GPIO_A, GPIO_B, and GPIO_C are the three GPIOs of the main control CPU. The main control CPU is the ARS31L from Coolchip Microelectronics.

[0065] The main control CPU controls the analog switch to switch the voltage divider resistor through three GPIO pins based on the transmit quality parameters (EVM) of the front-end module and the signal-to-noise ratio (SNR) of the received signal at the ground end. This dynamically adjusts the power supply voltage of the front-end module FEM, achieving adaptive control of low voltage for low transmit power and high voltage for high transmit power. When the EVM or SNR exceeds the preset qualified threshold, the power supply voltage is automatically increased until the EVM and SNR return to qualified levels.

[0066] This invention provides a voltage-adaptive UAV image transmission energy-saving system and method, relating to the field of UAV communication technology. The system includes a control unit, a radio frequency (RF) front-end module, an adjustable power supply system, and an electronic switching circuit. The adjustable power supply system includes a DC-DC converter with a feedback circuit. The control unit, based on the acquired transmit power of the RF front-end module, controls the electronic switching circuit to selectively connect one of multiple feedback resistors to the feedback circuit, thereby adjusting the output voltage of the DC-DC converter to achieve dynamic matching between the transmit power and the supply voltage. The method includes: determining the target transmit power required by the RF front-end module; determining the target supply voltage based on the target transmit power; and controlling the adjustable power supply system to output the target supply voltage. This invention solves the problem of excessive power consumption caused by fixed voltage supply in existing image transmission systems. By achieving dynamic matching between voltage and power, it significantly reduces system power consumption, extends UAV endurance, and simultaneously ensures communication quality and system stability.

[0067] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A voltage-adaptive UAV image transmission energy-saving system, characterized in that, include: A control unit for acquiring the transmit power of the radio frequency front-end module; An RF front-end module; An adjustable power supply system for powering the radio frequency front-end module, the adjustable power supply system including a DC-DC converter with feedback circuitry; as well as An electronic switching circuit is connected between the control unit and the feedback circuit; The feedback circuit includes multiple feedback resistors; The control unit is configured to: control the electronic switching circuit according to the acquired transmit power, so as to selectively connect one of the plurality of feedback resistors to the feedback circuit, thereby adjusting the output voltage of the DC-DC converter so that the transmit power of the RF front-end module matches the power supply voltage supplied to it.

2. The voltage-adaptive UAV image transmission energy-saving system according to claim 1, characterized in that, The control unit is configured to achieve low power transmission corresponding to low supply voltage and high power transmission corresponding to high supply voltage.

3. The voltage-adaptive UAV image transmission energy-saving system according to claim 1 or 2, characterized in that, The control unit is also configured to: Monitor the transmit signal quality parameter EVM of the RF front-end module, and when the monitored EVM is less than a first preset threshold, control the adjustable power supply system to increase the output voltage; and / or The signal-to-noise ratio (SNR) data is received and processed through the data interface of the ground end of the image transmission module. When the processed SNR is less than a second preset threshold, the adjustable power supply system is controlled to increase the output voltage.

4. The voltage-adaptive UAV image transmission energy-saving system according to claim 1 or 2, characterized in that, When the control unit adjusts the output voltage according to the transmission power, it uses a power switching hysteresis threshold.

5. The voltage-adaptive UAV image transmission energy-saving system according to claim 1, characterized in that, The electronic switching circuit includes a single-pole multi-throw analog switch controlled by the GPIO pin of the control unit.

6. A voltage-adaptive UAV image transmission energy-saving method, characterized in that, The voltage-adaptive UAV image transmission energy-saving system according to any one of claims 1 to 5 includes the following steps: Receive an instruction to determine the target transmit power required by the radio frequency front-end module; Based on the target transmission power, determine a target power supply voltage that matches it; The adjustable power supply system is controlled to output the target power supply voltage to the radio frequency front-end module.

7. The voltage-adaptive UAV image transmission energy-saving method according to claim 6, characterized in that, The step of determining the target power supply voltage follows the principle of matching low power supply voltage with low transmission power and matching high power supply voltage with high transmission power.

8. The voltage-adaptive UAV image transmission energy-saving method according to claim 6 or 7, characterized in that, Also includes: The transmit signal quality parameter EVM of the radio frequency front-end module is monitored in real time, and when the monitored EVM is less than a first preset threshold, the output voltage of the adjustable power supply system is increased based on the current target power supply voltage. and / or The system receives signal-to-noise ratio (SNR) data through a data interface of the image transmission system, and when the received SNR is less than a second preset threshold, it increases the output voltage of the adjustable power supply system based on the current target power supply voltage.

9. The voltage-adaptive UAV image transmission energy-saving method according to claim 6 or 7, characterized in that, In the control steps, when switching the target power supply voltage, a power switching hysteresis threshold is used for judgment, and the power switching hysteresis threshold is 0.5dB.

10. A drone, characterized in that, Including the voltage-adaptive UAV image transmission energy-saving system as described in any one of claims 1 to 5.

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